1. Field of the Invention
The present invention relates to a ladder program editing device, and more particularly to a ladder program editing device having a function of displaying a network comment on a search result display screen.
2. Description of the Related Art
An explanatory note of processing content may be added to a position in which it is appropriate for delimiting a process of a ladder program, and the explanatory note can be added in order to facilitate understanding of ladder processing content when the ladder program is viewed later or when the ladder program is viewed by a third party.
Typically, the ladder program is often created such that one function is implemented through several to several tens of lines of ladder circuits. For this reason, a technique of facilitating understanding of processing content by adding a tag or a comment to a ladder circuit and describing processing content of consecutive ladder circuits in order to help with understanding has been proposed (for example, see JP 10-320424 A and JP 2005-092807 A).
Further, an editing method of registering information such as a symbol or a comment at an address of each contact point in advance, displaying the information such as the symbol or the comment set to the address of each contact point through a sub screen, and making efficient a creation of a sequence program and an editing work has been proposed (for example, see JP 2003-295911 A).
FIG. 7 illustrates a display example of a ladder program in which a network comment serving as a sort of comment is registered. In FIG. 7, a network comment including an explanation related to a ladder circuit is displayed above each of ladder circuits configuring a ladder program.
Generally, as a search of a contact point of a ladder circuit, there are a method of jumping to a ladder program satisfying a search condition and displaying the ladder program and a method of acquiring ladder circuits satisfying a search condition from all ladder programs and displaying a list of acquired ladder circuits. FIG. 8 illustrates an example in which a search result is displayed on a list form in the latter case. As illustrated in FIG. 8, in the method of displaying a list of ladder circuits hit by search as a search result, it is easy to understand an overview of the search result, whereas since only the ladder circuits satisfying the search condition are displayed, there are cases in which it is difficult to determine a process performed by the ladder circuit and a position thereof.
In this case, it is necessary for the user to display a portion around an original position of a searched ladder circuit again and check processing content based on previous and subsequent ladder circuits, a previously note comment, or the like. As a result, it is necessary to perform a work of switching the search result list screen and the ladder screen and checking processing content of the ladder in order to search for a desired ladder circuit many times, and such a work is a big burden on the user.